Electric call



(No Model.) 2 Sheets-Sheet 1.

J. B. GU'RRIER.

BLEGTRIG CALL.

No. 425,594. Patented Apr. 15, 1890.

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UNITED STATES PATENT CEEICE.

JACOB B. CURRIER, OF LOWELL, MASSACHUSETTS, ASSIGNOR TO THE CUR- RIERTELEPHONE BELL COMPANY, OF MASSACHUSETTS.

ELECTRIC CALL.

. SPECIFICATION forming part of Letters Patent No. 425,594, dated April15, 1890.

Application filed October 1'7, 1881. Serial No. 43,989- (No model.)

To all whom, it may concern: Fig. is an edge view of the caller in itscase,

Be it known that I, JACOB B. CURRIER, of as shown in front View in Fig.5. Lowell, in the county of Middlesex and State The general system ofindividual bells here of Massachusetts, have invented certain newreferred to is shown and fully described in 5 and useful Improvements inElectric Calls my above-named Letters Patent, and its genand theApparatus Connected therewith, of eral operation need not be hereredescribed. which the following is a specification. On the circuit, 1,2, and 3 represent three My improvements relate to the electriccalldifierent stations provided with call bells, ing apparatus patentedto me August 30, 1881, having each a different length of spring- 10 byPatent No. 246,374; and they consist in tongue to give it individualaction with a placing the magnet and bell in a novel posiproper brokenor undulatory current. The tion relatively to the bell-hammer andmodicalling apparatus is placed at the central stafying the constructionof the latter, as heretion l. inafter described, whereby I am enabled toO O are the ground-connections at each end I 5 make thecalling-instrument operate more ofthe circuit. 5

surely and effectively in calling any particu- L is the battery. larbell; secondly, in providing the calling- B is the bell. A is itsmagnet. instrument with an automatic circuit-break- H is thebell-hammer. The hammer is ing mechanism when stationary to savebatplaced, according to my improvement here 20 tery-power and render theoperation of the claimed, between the magnet A and bell B, bells moreeffective; thirdly, in providing instead of having the magnetand bell onthe calling-instrument with a cam-shaped the same side of it. Thisarrangement is a drum or cylinder or equivalent crank-arm for greatimprovement on my former one for this enabling me to lengthen andshorten the vireason.

brating caller between any two bell-hammer In my former patent I haveexplained how lengths to the length of the one to be operated aspring-hammer enables itself to be kept over the line byasubstantiallyequal amount nearer to the vibrating time of the broken of rotation onits cam or crank axis to that reelectric current generated by thevibrating quired to adjust it between any other two spring g of thecollar than is possible with a 0 bell-hammer lengths; fourthly, inattaching free swinging pendulum, thus causing the to the axis on whichthe cam or crank of the bell-hammer to continue to strike the bellcalling-instrument moves a detent-lever and when once set in actioninstead of being providing the dial with a series of holes, into thrownout of striking time by rebounding which the detent fits, as hereinafterdescribed, from the bell, as a free swinging pendulum is.

3 5 to cause the crank-arm or drum to be brought By experiment, however,I have discovered and held in exactly proper position, and thus thatwhile the spring-hammer in sounding the readily give the vibratingcaller the proper bell keeps the time of its own vibration near lengthto call the desired station on the cirenough to that of the vibrativecurrent to cuit. thus continue to strike the bell, it does not 40Inthedrawings,Figurelshows an electrical with my former constructionexactly keep 0 circuit provided with a calling-instrument such time, andconsequently some part of the and a series of individual bells, thecaller electric force is wasted and the force of the having part of itsface broken away to show blow of the hammer on the bell is thus diminitsinternal construction. Fig. 2 represents ished percep'tibly. Suppose,for instance, a

45 a modification of the calling-instrument with spring bell-hammernormally vibrating two the face of its case partly broken away tohundred and forty times per minute is used show its internal mechanism.Fig. 3 shows with my former arrangement. Taking the the face of thecalling-instrument complete hammer in a state of rest, I am obliged toset ready for operation. Fig. i represents the the vibrating caller gso'that it will vibrate 50 individual bell of my improved construction.substantially two hundred and forty times per minute in order to set thehammer in motion by the vibrative current generated by the caller. Underthe action of this current the bell-hammer will be set in vibration atits normal rate and constantly increase its swing until it strikes thebell. In repeated striking of the bell the vibrating hammer will haveits rate increased somewhat above two hundred and forty times perminute, and its vibration thus varying from that of the currentgenerated by the caller, which remains constant, part of the electricforce is expended in acting against the spring while it is farthest awayfrom the magnet and least susceptible to its influence, and isaccordingly wasted.

My present arrangement overcomes this diificulty in the followingmanner, and produces a louder alarm with the same volume ofelectricforce. The magnet being on the opposite side of the hammer from thebell, the rebound of the hammer from the first blow on the latter sendsit with accelerated motion nearer to the magnet and directly into itsstrongest attractive force, giving it sufficient power to control themotion of the hammer. The magnet therefore holds onto the hammer anddetains it at the farthest point of its rebound from the bell until thecurrent is broken and the hammer released to spring forward againstthebell. This operation is constantly repeated and the hammer keptvibrating in time with the make and break of the current instead of outof that time, thus making the motion of the bell-hammerand vibratingcaller g coincide while the bell is being sounded. In order to aid thisaction of the magnet, I make the armature of the hammer and its strikingpartsubstantially in one piece and make the flexible part of it entirelybetween the hammer-armature and its point of support. This constructiongives the magnet V greater leverage over the striking-hammer, and at thesame time a larger mass of soft metal to act upon, thereby increasingits effi- 3 ciency. It also diminishes the amount of weight to becarried by the spring and en ables me to use several more bells on acircuit at'higher rates of vibration than was before I practicable.

My second improvement consists in so placing the lever in and itsspringnthat the battery-circuit will be connected with the line onlywhen the vibrating caller is in operation, and will be connected thenonly through the contact-point k of the vibrating caller. The callerwill thus automatically break the circuit at the instant that the leveris released. This prevents induced currents of electricity from? flowingover the circuit and the bell-hammer: armature from clinging to itselectro-magnet. g

The importance of this is considerable.

In the caller shown in Fig. 1, q is the line connected with the batterywhich is connected i to the caller-actuating lever-studp. The metal arm0 of the wooden lever m, which actuates the vibrating caller, comes intocontact with' the metal stud r when the lever m is moved out of the wayof the vibrating caller, "and the the battery-circuit. Suppose we havean electrical circuit with a bell at'station 1 vibrat-.

ing five hundred times per minute and one 2 at station 2 vibrating fivehundred and fifty If after using station 1 bell its hamy times. mer isimmediately released from magnetic influence by the breakiugbftheClTOlllt, I can therefore immediately can No. 2 bell; but if the circuitbe not thus broken there is a hability of sounding No. 1 bell in callingNo. 2,

because the hammer-armature may cling to its electro-magnet untilreleased bythe break first made in calling the next bell. The automat cbreaking of the circuit in the caller, as described, sensibly overcomesthis difficultyand enables me to place more'bells ona circuit.

Instead of the cylindrical wheel or drum 1) shown in the patent beforereferred to for lengthening and shortening my vibrating caller g, I haveadoptedacylinder rotati ngon the axial s'tud,which is provided with acran karm s, to which the upper end of the spring of the callerishttached, which with each for-.

ward movement of the index-hand attached to the cylinder will shortenthe spring vibrating part of the caller less than did the last precedingmovement of the index-hand through an equal space over thedial-face.Another form to accomplish thisis shown in Fig. 2, in which is acam-shaped cylinder which constantly diminishes the amount which itshortens the vibrating caller, as it continues to shorten it inproportion to 'a given amount of rotation. The reason of thisconstruction is that it requires a greater shortening of the vibratingcaller to adapt it to two bells adjacent in rate of vibration in thelower speeds than it does in the higher. For instance, suppose thelowest bell-ham-mer in vibration to be two hundred and forty times perminute and the next greater to be two hundred and ninety times perminute. It will require a much greater shortening'of the length of thecaller betweentheir lengths ITO than it would between thelengths'oftwobellhammers when the lowest vibrated one thousand times per minuteand the next highest vibrated one thousand and fifty times; hence Iproportion the cam shortenin'g cylinder or crank-arm so that with anequal amount of rotation on its axis it will so shorten the vibratingcaller as to adapt it to'two consecutive bells whether vibrating at thehigher or lower speeds. This enables meto move the dial-hand which isattached to the axis of this cam or arm over an equal space to call anybell after calling the next one below it in vibration.

' My fourth improvement consists in attaching to the index-hand b of thecylinder 1) an extension or prolongation b on the opposite side, of itsaxis from the hand and providing this prolongation with a pin or detentprojecting inward and made to accurately fit a series of holes in thedial-face 1' 2 3 &c. These holes are so placed that this prolongation ofthe pointer, being elastic, springs the detent into the hole at theexact point required to adapt the length of the vibrating caller g tosome one of the bell-hammers on the line. This not only saves time andcare on the part of the operator in calling any hell, but it is valuablein setting the index to call a bell having its hammer vibrating on ahigh number-as, for instance, eleven hundred vibrations perminute-because the higher the number of vibrations per minute thegreater the accuracy required in lengthening or shortening the vibratingcaller g to the exact extent necessary to operate the bell-hammervibrating at that rate. By means of the holes 1 2 3, &c., and theirdetent I am enabled to attain the greatest exactitude and celerity inthis respect, where it is so important. The detent also locks thecylinder in this exact position and prevents it from being moved byaccident.

What I claim as new and of my invention 1. The combination of anelectric circuit, a vibrating circuit-breakin g mechanism thereinarranged to make and break the circuit regularly and automatically at apredetermined rate of vibration, and an alarm mechanism in said circuit,consisting of magnet A, bell B, and the vibrating striker H, locatedbetween them, provided with an armature and arranged to automaticallyvibrate synchronously with said circuit-breaker, whereby the variationin the rate of vibration of the striker produced by its blow upon thebell will be overcome by the magnet upon the rebound of the strikertoward it, substantially as described.

2. The combination of an electric circuit, a vibrating circuit-breakin gmechanism therein arranged to make and break the circuit regularly andautomatically at a predetermined rate of vibration, and an alarmmechanism in said circuit, consisting of magnet A, bell B, and thevibrating striker I-l, having its striking part and armature formed ofone rigid piece of metal and its elastic part en-.

tirely between the latter and its point of support, said striker beingarranged to automatically vibrate synchronously with saidcircuitbreaker, whereby the production of secondary and interferingvibrations between the armature and striking part of the striker by itsblow upon the bell and the consequent disturbance of its synchronousvibration are avoided, substantially as described.

3. The combination of an electric circuit, the vibrating circuit-breakerg, having its spring portion adjusted to make and break the circuitautomatically at a predetermined rate of vibration and to be held inposition to break the circuit when its vibration ceases, and two alarmmechanisms in said circuit, one of which has the spring portion of itsstriker adjusted to automatically vibrate synchronouslywith said rate ofvibration of the circuit-breaker and the other of which has the springportion of its striker adjusted to vibrate at a substantially differentrate of vibration not affected by the circuit-breaker, substantially asdescribed.

4. In combination with the circuit of individual call-bells, the callerg and its arm I), provided with the arm I) and its detent, and thecorresponding holes 1 2, &c., placed to adjust the caller to the lengthto call one or more of said bells, substantially as described.

JACOB B. CURRIER.

